KR100197902B1 - Compounding compositions for airing film - Google Patents

Abstract

The present invention relates to a compound composition for breathable film, and more particularly, to a compound composition for breathable film, 100 parts by weight of polyethylene resin having a low melt index, 10 to 30 parts by weight polyethylene resin having a high melt index and a filler It relates to a compound composition for breathable film consisting essentially of 120 to 200 parts by weight.

Description

Compound composition for breathable film

The present invention relates to a compound composition for breathable film, and more particularly, to a compound composition for breathable film, which is easy to process, has excellent mechanical properties, stable physical properties, and excellent breathability.

The breathable film can be applied to hygiene products such as diapers, sportswear, clothing, wallpaper, wraps, raincoats, and packaging for fragrance products, because water vapor permeates and does not permeate liquids such as water.

As a method of manufacturing the air permeable or porous film, (1) forming a fine hole in the molded film by electric shock and mechanical impact, (2) mixing the inorganic filler or organic filler with polyolefin resin and then uniaxially or biaxially A method of forming fine pores by interfacial separation between a resin and a filler by stretching, (3) a method of forming fine pores by volatilizing a solvent by a heating method after mixing the resin and a solvent and performing primary molding; And (4) mixing the resin with the inorganic filler to form a film, and then removing the inorganic filler by chemical treatment to form fine pores.

Among the above methods, the process is easy and the production cost is low, the present invention also relates to the same method as in the above (2).

On the other hand, a method for producing a breathable film by adding an inorganic filler has been proposed in Japanese Patent Laid-Open No. 61-121925, 62-18435, or 62-27438, but to increase the air permeability without deteriorating physical properties There was a technical limitation. In general, in order to obtain a film having a high air permeability, there is a method of increasing the amount of filler or using a high density resin, but in the former case, there is a disadvantage in that it is difficult to process with deterioration of physical properties. This increases the disadvantage of poor touch and severe heat shrinkage.

Accordingly, an object of the present invention is to maintain the amount of the filler in order to compensate for the above-mentioned disadvantages, while not only exhibiting excellent processability, but also designing the compound to facilitate the interface separation between the resin and the inorganic filler during film stretching, The present invention relates to a compound composition for breathable films that can produce a film having excellent strength and feel, and which can exhibit appropriate air permeability and physical properties according to the use of the film.

The composition of the present invention for achieving the above object is essential in the compound composition for breathable film, 100 parts by weight of polyethylene resin having a low melt index, 10 to 30 parts by weight polyethylene resin having a high melt index and 120 to 200 parts by weight of a filler Is done.

Looking at the present invention in more detail as follows.

In the present invention, the problem of the existing breathable film was solved by mixing a polyethylene resin having a low melt index and a polyethylene resin having a high melt index. In other words, by mixing a polyethylene resin having a high molecular weight (inversely proportional to the melt index) and a polyethylene resin having a low molecular weight, it was possible to improve the air permeability of the final film without deteriorating other physical properties.

The melt index of the polyethylene resin having a low melt index is preferably in the range of 1.0 to 5.0 regardless of the density of the resin in terms of physical properties of the film, and the melt index of the polyethylene resin having a high melt index is similar to that of the resin. It is preferable that it is 15-35 under the conditions which have the viewpoint of the interfacial separation property of a resin and an inorganic filler, and film processability at the time of operation.

Examples of the polyethylene resin having a low melt index used in the present invention is a linear low density polyethylene resin having a density of 0.919 to 0.925 g / cm ³ , a melt index of 1.0 to 3.0 or a density of 0.928 to 0.934 g / cm ³ , melting A medium density polyethylene resin having an index of 2.0 to 3.5 is preferred, and a polyethylene resin having a high melt index is preferably a linear low density polyethylene resin having a density of 0.919 to 0.925 g / cm ³ and a melt index of 15 to 35. It is not limited to this. Here, the melt index of the resin is measured according to KS M3012, and the unit is g / 10 min unless otherwise noted.

On the other hand, the polyethylene resin having a high melt index is mixed with 10 to 30 parts by weight based on 100 parts by weight of polyethylene resin having a low melt index, wherein if less than 10 parts by weight, the interfacial separation between the resin and the inorganic filler during stretching is lowered When the amount exceeds 30 parts by weight, the physical properties of the film are lowered.

As the filler used in the present invention, calcium carbonate or barium sulfate is preferable, and the amount used is 120 to 200 parts by weight. At this time, if the water content is less than 120 parts by weight, the moisture permeability is lowered. In addition, the average particle size of the calcium carbonate is preferably 0.8 to 1.5㎛, the average particle size of the barium sulfate is preferably 1 to 3㎛.

According to an embodiment of the present invention, the composition of the present invention has a density of 0.919 to 0.925 g / cm ³ , 100 parts by weight of linear low density polyethylene resin having a melt index of 1.0 to 3.0, the density is 0.919 to 0.925 g / cm ³ It is essentially composed of 10 to 30 parts by weight of linear low density polyethylene resin having a melt index of 15 to 35 and 120 to 200 parts by weight of a filler.

According to another embodiment of the present invention, the composition of the present invention has a density of 0.928 to 0.934 g / cm ³ , 100 parts by weight of a medium density polyethylene resin having a melt index of 2.0 to 3.5, the density of 0.919 to 0.925 g / cm ³ It is essentially composed of 10 to 30 parts by weight of the linear low density polyethylene resin having a melt index of 15 to 35, and 120 to 200 parts by weight of the filler.

On the other hand, in addition to the above components, the resin components commonly added in the manufacture of breathable films include low density polyethylene, ethylene vinyl alcohol, and / or ultra low density polyethylene, and other additives include titanium dioxide, antioxidants, processing aids, calcium stearate and / or Zinc stearate, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited to the following Examples.

Comparative Example 1

In this comparative example, an inorganic filler is blended with a linear low density polyethylene for film (MI = 1.0 to 3.0, density = 0.919 to 0.925, hereinafter referred to as LLDPE 1) to prepare a compound for breathable film.

LLDPE 1 100 parts by weight of low-density polyethylene (MI = 5 ~ 7, density = 0.99, hereinafter LDPE) 15 parts by weight, ethylene vinyl alcohol (15% vinyl acetate content, hereinafter called EVA) 8 parts by weight, white pigment 5 parts by weight of titanium dioxide, 0.3 parts by weight of primary and secondary antioxidants (Ciba-Geigy Co., Ltd., IRGANOS 1010 (1st), IRGAFOS 168 (2nd)) ) 0.3 parts by weight, calcium stearate and zinc stearate were mixed 0.8 parts by weight, respectively, and then mixed for 3 minutes in a supermixer, melt mixed and extruded by mixing with 130 parts by weight of calcium carbonate having an average particle size of 0.8 to 1.5 μm. Processed in pellet form. The processed compound was uniaxially stretched in a T-die film forming machine to prepare a breathable film having a basis weight of 35 g / m ² , and the results are shown in Table 1 below. Here, basis weight is the weight which occupies per square meter of film, and a unit is g / m <^2> .

Example 1

In Comparative Example 1, instead of reducing the content of LDPE and EVA, except for using 20 parts by weight of high linear low density polyethylene (MI = 15-35, density = 0.919-0.925, hereinafter referred to as LLDPE 2), breathable in the same manner A film was prepared and the results are shown in Table 1 below. According to the results, the film workability was improved, the occurrence of pinholes was significantly reduced, and the moisture permeability was greatly improved.

Comparative Example 2

Except having changed the kind of inorganic filler into the barium sulfate whose particle average size is 1-3 micrometers, it is the same as the comparative example 1, The result is shown in following Table 1.

Comparative Example 3

Except that the content of LLDPE 2 to 30 parts by weight or more, the same as in Example 1, the results are shown in Table 1 below. The flowability and water vapor transmission rate of the compound is improved than the conventional compound, but the physical properties are lowered.

[Comparative Example 4]

A breathable film was prepared in the same manner as in Comparative Example 1 except that 20 parts by weight of polypropylene having a high MI (MI = 15 to 25, hereinafter PP) was used instead of reducing the content of LDPE and EVA. It is shown in Table 1 below.

[Comparative Example 5]

In this comparative example, an inorganic filler is blended with medium density polyethylene (MI = 2.0-3.5, density = 0.928-0.934, hereinafter MDPE), and the compound for breathable films is manufactured.

100 parts by weight of MDPE, 20 parts by weight of LDPE (MI = 5-7, density = 0.919), 10 parts by weight of ultra low density polyethylene (MI = 1 ~ 3, density = 0.910, hereinafter VLDPR), and titanium dioxide as a white pigment 5 parts by weight, 0.6 parts by weight of primary / secondary antioxidants (Ciba-Geigy, IRGANOS 1010 (1st), IRGAFOS 168 (2nd)), 0.3 parts by weight of processing aid (3M, DYMAMER), stearic acid Calcium and zinc stearate were mixed 0.8 parts by weight, respectively, and then mixed in a supermixer for 3 minutes, melt mixed with 140 parts by weight of calcium carbonate having an average particle size of 0.8 to 1.5 µm in a twin screw extruder, and processed into pellets. The processed compound was uniaxially stretched in a T-die film forming machine to prepare a breathable film having a basis weight of 35 g / m ² , and the results are shown in Table 1 below. It has excellent physical properties and moisture permeability but has some disadvantages in processability.

Example 1

Except for reducing the content of LDPE and VLDPE in Comparative Example 5, except for using 20 parts by weight of LLDPE 2 to prepare a breathable film in the same manner, the results are shown in Table 1 below. Processing is easy and the occurrence of pinholes is significantly reduced.

Physical properties shown in Table 1 were measured by the following method.

● Water vapor permeability: According to ASTM E96-92, after keeping for a certain period of time under the condition of constant temperature and humidity of 37.8 ℃ and relative humidity of 90%, measure the water vapor permeability according to the weight increase, and g / m 24hrs.

Tensile strength: Tensile strength at 3% elongation and tensile strength at break were measured according to the machine direction (hereinafter referred to as MD) and machine vertical direction (hereinafter referred to as CD) according to KS M3016.

Elongation: Elongation at break along MD and CD directions was measured according to KS M3016.

● Film Appearance: Observe the film's pinhole frequency [open / (600m × 1.7m)] due to foreign substance or gas generation or visually identify whether the film is mixed with undispersed product.

◎: Pinhole occurrence frequency is less than 1 and undispersed product is not observed.

(Circle): The frequency of pinhole occurrence is 2 or more and some undispersed thing is observed.

(Triangle | delta): Many pinhole occurrences and many undispersed products are observed.

● Film processability: Film processability is as follows based on the highest extrusion amount that good film is produced.

◎: Good process for forming film with low processing load and high extrusion volume.

○: Processing load and extrusion amount are normal.

(Triangle | delta): It takes a lot of processing loads, and becomes a film molding only by reducing extrusion amount.

Claims (8)

In the compound composition for breathable film, 200 parts by weight of polyethylene resin having a relatively low melt index of 1.0 to 5.0, 10 to 30 parts by weight of polyethylene resin having a relatively high melt index of 15 to 35, and Compound composition for breathable film, consisting essentially of 120 to 200 parts by weight of the filler. The method of claim 1, wherein the polyethylene resin having a low melt index has a density of 0.919 to 0.925g / cm ³ , a linear low density polyethylene resin having a melt index of 1.0 to 3.0 or a density of 0.928 to 0.934g / cm ³ , melting Compound composition for breathable film, characterized in that the medium density polyethylene resin having an index of 2.0 to 3.5. The compound composition for breathable film according to claim 1, wherein the polyethylene resin having a high melt index is a linear low density polyethylene resin having a density of 0.919 to 0.925 g / cm ³ and a melt index of 15 to 35. The polyethylene resin of claim 1, 2 or 3, wherein the polyethylene resin having a low melt index is a linear low density polyethylene resin having a density of 0.919 to 0.925 g / cm ³ and a melt index of 1.0 to 3.0. Compound composition for breathable film, characterized in that the polyethylene resin having an index is a linear low density polyethylene resin having a density of 0.919 to 0.925g / cm ³ and a melt index of 15 to 35. The method of claim 1, 2 or 3, wherein the polyethylene resin having a low melt index is a medium density polyethylene resin having a density of 0.928 to 0.934 g / cm ³ , the melt index is 2.0 to 3.5, the high melting Compound composition for breathable film, characterized in that the polyethylene resin having an index of 0.919 to 0.925g / cm ³ density, linear low density polyethylene resin having a melt index of 15 to 35. 2. The compound composition for breathable film according to claim 1, wherein the filler is calcium carbonate or barium sulfate. The compound composition for breathable film according to claim 6, wherein the average particle size of the calcium carbonate is 0.8 to 1.5 mu m. 7. The compound composition for breathable film according to claim 6, wherein the barium sulfate has an average particle size of 1 to 3 mu m.